Page metadata

A page names its title and its head tags, and the root layout writes them once.

Say it in the page

For a page that never changes, write a literal at the top of the frontmatter:

src/routes/blog.nexy

---
metadata = {"title": "Blog", "description": "Posts about Nexy"}
---
<h1>Blog</h1>

When the title depends on the data, call setMetadata instead:

src/routes/posts/[slug].nexy

---
from nexy import notFound, setMetadata

from src.posts import find

slug: prop[str]
post = find(slug) or notFound()
setMetadata(title=post.title, description=post.summary, og={"image": post.cover})
---
<h1>{{ post.title }}</h1>

A modular controller calls setMetadata(...) before it returns useViews(...).

Write it in the layout

The root layout owns the <head>. One line writes what the page said, escaped:

src/routes/layout.nexy

---
from nexy import setMetadata, useMetadata

children: prop[NexyElement]
setMetadata(title_template="%s | My site")
---
<!DOCTYPE html>
<html>
  <head>
    {{ useMetadata().html() }}
  </head>
  <body>{{ children }}</body>
</html>

A page runs before its layouts, so the layout finds what the page asked for. A page that says nothing gets the useTitle of your nexyconfig.py, and no other tag.

The fields

Field	Written as
`title`	`<title>`; with `title_template="%s \| My site"` the title is put in the `%s`
`description`	`<meta name="description">`
`canonical`	`<link rel="canonical">`
`robots`	`<meta name="robots">`, for example `"noindex"`
`icon`	`<link rel="icon">`
`og`	one `<meta property="og:...">` per key: `{"image": "/cover.png"}` gives `og:image`
`twitter`	one `<meta name="twitter:...">` per key
`extra`	a list of attribute dicts, one `<meta>` each: `[{"name": "theme-color", "content": "#fff"}]`

A later call replaces a value; og, twitter and extra add to what is there. A field that does not exist raises TypeError, so a typo does not silently do nothing.

Safe by default

Every value is HTML-escaped, so a title built from a URL or from the database cannot close the tag and inject a script. A value is escaped once, when the layout calls html(): do not escape it yourself.

Next steps

Edit on GitHub